1 files changed, 112 insertions, 0 deletions
diff --git a/bin/tests/system/wildcard/tests_wildcard.py b/bin/tests/system/wildcard/tests_wildcard.py
new file mode 100755
index 0000000..66166f2
--- /dev/null
+++ b/bin/tests/system/wildcard/tests_wildcard.py
@@ -0,0 +1,112 @@
+#!/usr/bin/python3
+
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0.  If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+"""
+Example property-based test for wildcard synthesis.
+Verifies that otherwise-empty zone with single wildcard record * A 192.0.2.1
+produces synthesized answers for <random_label>.test. A, and returns NODATA for
+<random_label>.test. when rdtype is not A.
+
+Limitations - untested properties:
+    - expansion works with multiple labels
+    - asterisk in qname does not cause expansion
+    - empty non-terminals prevent expansion
+    - or more generally any existing node prevents expansion
+    - DNSSEC record inclusion
+    - possibly others, see RFC 4592 and company
+    - content of authority & additional sections
+    - flags beyond RCODE
+    - special behavior of rdtypes like CNAME
+"""
+import pytest
+
+pytest.importorskip("dns")
+import dns.message
+import dns.name
+import dns.query
+import dns.rcode
+import dns.rdataclass
+import dns.rdatatype
+import dns.rrset
+
+pytest.importorskip("hypothesis")
+from hypothesis import given
+from hypothesis.strategies import binary, integers
+
+
+# labels of a zone with * A 192.0.2.1 wildcard
+WILDCARD_ZONE = ("allwild", "test", "")
+WILDCARD_RDTYPE = dns.rdatatype.A
+WILDCARD_RDATA = "192.0.2.1"
+IPADDR = "10.53.0.1"
+TIMEOUT = 5  # seconds, just a sanity check
+
+
+# Helpers
+def is_nonexpanding_rdtype(rdtype):
+    """skip meta types to avoid weird rcodes caused by AXFR etc.; RFC 6895"""
+    return not (
+        rdtype == WILDCARD_RDTYPE
+        or dns.rdatatype.is_metatype(rdtype)  # known metatypes: OPT ...
+        or 128 <= rdtype <= 255
+    )  # unknown meta types
+
+
+def tcp_query(where, port, qname, qtype):
+    querymsg = dns.message.make_query(qname, qtype)
+    assert len(querymsg.question) == 1
+    return querymsg, dns.query.tcp(querymsg, where, port=port, timeout=TIMEOUT)
+
+
+def query(where, port, label, rdtype):
+    labels = (label,) + WILDCARD_ZONE
+    qname = dns.name.Name(labels)
+    return tcp_query(where, port, qname, rdtype)
+
+
+# Tests
+@given(
+    label=binary(min_size=1, max_size=63),
+    rdtype=integers(min_value=0, max_value=65535).filter(is_nonexpanding_rdtype),
+)
+def test_wildcard_rdtype_mismatch(label, rdtype, named_port):
+    """any label non-matching rdtype must result in to NODATA"""
+    check_answer_nodata(*query(IPADDR, named_port, label, rdtype))
+
+
+def check_answer_nodata(querymsg, answer):
+    assert querymsg.is_response(answer), str(answer)
+    assert answer.rcode() == dns.rcode.NOERROR, str(answer)
+    assert answer.answer == [], str(answer)
+
+
+@given(label=binary(min_size=1, max_size=63))
+def test_wildcard_match(label, named_port):
+    """any label with maching rdtype must result in wildcard data in answer"""
+    check_answer_noerror(*query(IPADDR, named_port, label, WILDCARD_RDTYPE))
+
+
+def check_answer_noerror(querymsg, answer):
+    assert querymsg.is_response(answer), str(answer)
+    assert answer.rcode() == dns.rcode.NOERROR, str(answer)
+    assert len(querymsg.question) == 1, str(answer)
+    expected_answer = [
+        dns.rrset.from_text(
+            querymsg.question[0].name,
+            300,  # TTL, ignored by dnspython comparison
+            dns.rdataclass.IN,
+            WILDCARD_RDTYPE,
+            WILDCARD_RDATA,
+        )
+    ]
+    assert answer.answer == expected_answer, str(answer)